1. Field of the Invention
The present invention relates generally to conventional photographic cameras and more particularly to an electronic imaging module that is removably insertable therein for reversibly converting such a conventional camera into an electronic imaging camera.
2. Description of the Prior Art
In conventional photographic cameras, image recording typically is performed by sequentially projecting optical images of subjects onto a roll of film formed from a silver halide based emulsion. Photons strike chemical grains in the silver halide emulsion and form a latent images that are stored in the emulsion. After completing exposure of all the frames on the roll of film, the latent images are developed by chemical processing and are viewed directly or printed on positive paper.
While conventional photographic camera and film systems do produce high resolution, continuous tone photographs at modest cost, such systems do have certain limitations. For example, image storage and retrieval is inconvenient and time consuming, and it is difficult and costly to copy, modify or transmit photographic images. Also, to use such images in electronic computer or video systems, the photographic image must first be converted to an electronic image in the form of an electrical signal which is representative of the photographic image.
To overcome these limitations, cameras have been implemented with special electronic means such as a charge-coupled device (CCD) for recording images electronically and a storage device such as a tape, disk or a memory circuit for storing electrical image signals. The image signals are transferred to a display device like a CRT for direct viewing or a printer for printing. The advantages are that the electronic images can be easily modified in format, resolution, color mapping, and special optical effects can be added. Also, the images may be easily transmitted to remote locations.
Electronic imaging systems incorporating the foregoing features are well known. For example, U.S. Pat. No. 4,916,476, issued to McGarvey, discloses an electro-optical circuit for converting a conventional single lens reflex (SLR) camera into an electro-optical camera. The electro-optical circuit is attached to the film back of the camera so that it is operational as a still camera or as an electro-optical camera.
U.S. Pat. Nos. 4,953,029 issued to Morimoto et al. and 4,814,811 issued to Saito et al. disclose still camera systems that are capable of being loaded with film backs or still video backs 2 for forming an image and transferring it onto a magnetic media.
U.S. Pat. No. 4,862,293 issued to Saito et al. discloses a still video adapter attached to a still video back at the rear cover of a SLR camera body. The still video adapter includes a CCD for receiving an image of an object photographed, a signal processing circuit for processing and transferring the image data to a magnetic disk attached to the side of the camera.
Another electronic still camera system using an adapter is shown by Holland in Electronic Photography and the NASA Experience. In this system, there is shown a removable hard drive attached to the side of a Nikon F4 camera via an adapter. Images are recorded on the hard drive and sent to a control station for viewing and printing.
U.S. Pat. No. 5,150,215 issued to Shi, discloses a camera system having film and still video functions. This camera operates in three modes. In the first mode, the camera is in a still video image mode only. In the second mode, the camera is in the photo film mode only. In the third mode, the camera is in the still video image mode and the film photo mode simultaneously.